My better half came home this evening after driving the 240D and said "Honey, the car smells funny..." Immediately after walking out the front door the fragrant smell of coolant hit my nose, however there was no coolant on the ground. Opening the hood revealed an extremely hot, slightly smoking engine. Turning the key to the on position showed the temp gauge pegged all the way to the top! It took 4 hours for the car to cool down (Still 100 degrees and it's after 10:00pm). Checking the radiator showed no coolant and after I started to refill the radiator the coolant started running out of the water pump weep hole. I have now drained the radiator coolant into a sealed container.
The good news is that the engine still started after it cooled down (I ran it for about 15 seconds). The bad news is that I do not know everything that I should look for before I start spending $$$. Please add to the list and correct any shade tree assumptions on my part...

1) Check compression to make sure valves and head gasket are OK. Is it possible to have burned the valves and warped the head and still get a good compression check?

2) Check for coolant in the oil. If there is coolant in the oil do I assume cracked block?

ouch that sucks. I'd refill the radiator with water and water and water wetter and drive it around. If everything feels normal (no excessive or out of the norm smoke), just as "smooth", just as "powerful", I'd probably just leave it that way.

Do check for oil in the coolant after that.

I think you should also check if the cooling system is still pressurized overnight. (If I'm not wrong that means it's bad...)

oh well.. sorry to hear that. I hope everything works out fine!
maybe if you posted this in the Diesel forum you'd get more reply!

I wouldn't worry too much, at least if the engine works after you put water in it. It looks like the water pump failed (in any case it doesn't hold the water ). So I would take it off and change the bearing and seal (or how you call that).
240D are tough cars, so

Here's the update on the 240D. The parts came in yesterday and I just finished putting in the new water pump. While I was at it I changed both fuel filters and the air filter. I went ahead and filled the radiator with a coolant / water mix at a 50/50 ratio and started her up. Amazingly, she seems to be running fine. I ran her for 20 minutes in traffic and she never got over 90 on the temp. There doesn't appear to be any loss of performance (as if she ever had any to begin with...) or water in the oil or oil in the water.

Ain't cast iron heads great .
When I first purchased my 300D unbeknowest to me it had a broken upper radiator hose connection. I was driving within about 4 miles of the house and saw water coming up over the hood from the front. Drove on home and found that the upper radiator hose had come off. Later on, I did have to replace the head gasket because of pressure in the coolant system after standing overnight but the car was running great with no obvious problems other than that.

My wife did the same to her beautiful 300TD turbo about 10 years ago. After I got the leak stopped and everything going again, it never used any oil or showed in ill effects whatsoever. I ultimately traded it to a local independent Benz tech. It is still his wifes car and they still drive it alot. The engine still has not been apart and he says it's the best running turbo diesel he ever had.

These are all iron engines and they don't have their reputation for nothing.